Versatile Superlubricity via Boronizing on Engineering Alloys: Insights into In Situ Passivation Mechanism

Area of Science:

• Materials Science
• Tribology
• Surface Engineering

Background:

• Superlubricity (<0.01 friction coefficient) offers significant energy savings and reduced CO2 emissions.
• Existing superlubricity methods are limited to specific materials, inert environments, or micro/nano-scales.

Purpose of the Study:

• To develop a versatile superlubricity strategy for common engineering alloys in atmospheric environments.
• To demonstrate a novel surface passivation principle for achieving ultra-low friction.

Main Methods:

• Electrochemical boronizing surface treatment of alloys.
• Application of polyol/water mixture lubricants.
• Atomistic simulations and experimental validation.
• Surface characterization using octadecyltrichlorosilane (OTS) for comparison.

Main Results:

• Achieved superlubricity (friction coefficient <0.01) on common engineering alloys under atmospheric conditions.
• Demonstrated wide adaptability to various alloys, high load capacity, and high-temperature resistance (≈125°C).
• Identified weak interactions between lubricant molecules and a C-H terminated tribofilm as the mechanism for friction reduction.

Conclusions:

• Surface passivation via electrochemical boronizing enables universal superlubricity in engineering alloys.
• The developed strategy has potential for industrial-scale applications, reducing energy consumption.
• Mechanochemical reactions forming a passivation layer are key to achieving superlubricity.